When I graduated college I went to work for Porcine Breeding stock company. Even with a Bachelors degree they started you out at the research/production farms for a year or so.
When working in the farrowing department, I used to castrate hundred of male pigs a day. The guy whose position I took over said that the faster you can do it, the less stress on the animal. I got so I could do 1 ever 6 seconds. Did 10s of thousands in that year.
Delaying castration just makes it harder for those boars who identify as sows because the operation will be more stressful later on. Better to start that transitioning early.